Microlens arrays are used in many applications where gathering light from a source and then directing it to various locations and at various angles is desirable. Such applications include computer displays, screens for projection televisions, illumination devices and other applications. When coated with reflective materials, such arrays can function as retroreflectors, reflecting light from a source back in the direction from which it entered the material. The array can include an aperture mask which only permits light to pass through the array in certain directions and which absorbs ambient light which would otherwise reflect off of the surface of the array and potentially degrade the contrast of the optical system. Such masks with apertures may be conventionally formed at the points where the microlenses focus paraxial radiation.
Conventional techniques for creating microlens arrays with aperture masks may involve fabrication of the arrays on suitable substrates which are or can be coated with appropriate radiation absorbing mask materials. High intensity radiation is then directed through the lenses and focused by them. If the structure of the lens array, substrate and mask has been designed so that the focal points of the lens array are at or near the mask layer, the radiation can form apertures in the mask at these focal points. See, for example, U.S. Pat. No. 4,172,219 to Deml et al., entitled Daylight Projection Screen and Method and Apparatus for Making the Same and U.S. Pat. No. 6,967,779 to Fadel et al., entitled Micro-Lens Array With Precisely Aligned Apertures Mask and Methods of Producing Same.
The design and manufacture of front projection screens may present design and manufacturing challenges. In particular, it may be desirable to provide high gain, high contrast screens for use with data projectors to exploit emerging opportunities in the home theater market and/or for other applications. Existing commercial screens are generally white or gray matted finish and may produce poor contrast, poor color saturation, and/or washed out black rendering under normal ambient lighting. These screens may also lack the ability to differentiate between projector light, which contains the desired image information, and ambient light, which contains light that can wash-out the image.